designing a fast rowboat

It looks like a freestyle kayak from about eight years ago when cartwheels were the in move so super slicey low volume ends were desirable. The advance to poppy moves like full loops saw the ends become higher volume again with the length as short as possible.

 

I'm not sure how many of those are actual words, but yeah, that's what it is.

Unfortunately, I don't think they make those in size extra fat ***, so I'll probably never own one.

 

Here in the UK we have a new design in production called the Clovelly Scull. I have looked back through the thread and have not seen it mentioned. My apologies if it has been already covered.

Here is a video of this sliding rigger design in action.

http://www.clovellysculls.co.uk/multimedia.php

How do you guys feel about sliding rigger? It just seems to make so much sense - to not move the body mass backwards and forwards wasting energy, yet attain the benefit of lower body power. I had a go in this design and it felt very natural in use.

The design ended up being very expensive to produce, but hopefully will gain sales. It can be seen that the hull is derived from the International Canoe, a somewhat strange place to start. It certainly has good ability in rough water.

Since it was derived from the IC hull I had a search for IC hull building and found a site where they had built a tortured ply IC hull, so I began to wonder if there was a good rowboat design using this technique. Until now have not had much success, but I have been following flo-mo's posts on the WBF and really like Big Guide, and am now even more pleased to see this new tortured ply design.

You see, I have some lovely 4mm Bryunzeel plywood which will be perfect to build such a design. I do hope flo-mo develops this design and releases the plank shapes. In fact I think a development class for such a two sheet tortured ply boat would be terrific. Low costs and quick build times would mean new ideas could be tried and tested so quickly and cheaply that much would be learnt and lots of fun had along the way.

Brian

 

Row Wing Sliding Rigger Conversion Kit

Howdy-

Just curious about this, I have read a bit about the sliding rigger vs sliding seat but it just seems few real implementations & not sure why not...
My present & first rowboat is a 15' clc Chester Yawl and for my own modest purposes, it seems in theory to offer a couple of real advantages:
1) at only 15', with a Piantedosi sliding seat/row wing in her there is some pitching fore & aft with the slide... I would think the sliding rigger would reduce this somewhat, as well as increase her speed a bit for similar effort.
2) Also, perhaps some better stability in rougher waters as your weight stays centered...?


So - with this in mind, has anyone yet to try the conversion kit that Piantedosi offers for their usual sliding row wing? $165 on the Rowalden web site, no diagrams or info otherwise. Just this photo here:

 

Yes, it would be good to have feedback from a sliding rigger user. One other company who produce sliding rigger boats are Virus Boats. Any Virus users?

 

One thing I've wondered about is comfort over any distance. I haven't tried sliding riggers, and I can see the possible benefits, but with a sliding rigger boat you're basically shoving the boat along with your butt since your feet aren't attached to the boat. This seems odd to me and I have read reports which said that comfort can be a problem. Butt chafe can be nasty even with a standard setup.

How long did you row the boat for?

 

It was just a short try out across Beale park lake at a show. However, Chris Partridge, of Rowing for Pleasure blog, http://rowingforpleasure.blogspot.com/ , did write a test report for Water Craft Magazine. here is a link to a preview of the article

http://www.exacteditions.com/exact/browse/603/1075/6796/2/57?dps=on

Brian

 

Hi, I'm new here and am excited to find this forum. I'm building a Bolger stretched dory and I would like some help picking the right length of oars for this boat. I would like to have a oar that can be used in calm and rough weather. I'm 6'2'' and have rowed quite a bit, but not recently. I am also going to build a set of hollow oars using the birdsmouth joint and would appreciate recommendations on thickness and width of strips, Thanks and Happy New Year

 

Some info here http://www.ehow.com/how_6779843_size-boat-oars.html

The outboard to inboard length ratio is effectively a gear ratio, the dimensions here may be too low a gear for a fast boat. Also for a larger blade size a slightly lower "gear" will reduce strain on the body. There is a lot of information on the web that you will find if you google Rowing Oar Dimensions or Sizing or something like that. You may not get them perfectly right the first time but building them is half the fun IMHO!

I can't help you with oar construction details, but I have built hollow masts. In addition to the birdsmouth joint which requires precision, you can simply bevel the edges of the staves - at 22.5 deg for eight sides. With this approach the staves are lined up on a table, with bevels up and edges snugged together along the full length, with strips of duct tape underneath about 12 inches apart. After the glue is inserted in the grooves between staves - not forgeting the end bevel (I did once!) - the whole thing is simply rolled up. No jigs are needed, the tape keeps the edges aligned. Use plastic cable clamps to close the seams after rolling. I find the assembly will glue up straight even if the staves are not perfectly straight and flat, provided they are well pressed down onto the tape. It is a lot easier to bevel the staves before they are cut off of the plank! With this method the excess glue tends to stay inside, with very little showing to clean off.

Good luck and don't forget the pictures ...

 

Thoughts on the Clovelly Skull:

The high bow and low stern gives an interesting appearance.

Not sure the underwater shape is optimum given that it's unlikely someone rowing will have the boat planing, unlike an IC which is one of the faster monohull sailboats for it's length from which the shape was derived.

The boat has a retractable, pivoting skeg which a review in Water Craft said it was needed to keep the rear end from slewing, presumably due to the flat sections in the stern. Net result of the shape and skeg is probably increased wetted surface area, and the slot for skeg adds drag.

The bipod in the stern supports a forward-view mirror and a GPS. Looks to me like it would be added windage. My thought would be to mount the mirror and GPS much lower, off the rail aft of the sliding rig, perhaps with a mirror on each side.

 

Thanks for the reply, this is as far as I've got, but summer's a long way off

 

Took our new Hanningfield Skiff out on Monday racing at Maldon rowing race, 30 odd entries, a real menagerie of different boats.
Crew myself my good lady wendy & our son Nick aged 14, Ann adams coxed, got a great start & rapidly overtaken by another randan skiff with very strong crew. Came in fourth overall & second in class, then found that we had been disqualified along with half the fleet for going the wrong side of a mark.
Arrgh!!! as it was a charity race in aid of the RNLI we couldnt whinge too much but will be more careful next time. Still better than last years race when apparently there was a punch up over some of the results!
Here is a link to show several of the boats i have either rebuilt or built new,
http://s1114.photobucket.com/albums/k533/keith667/,
The Gig Dauntless is 26ft long & goes quite well i suspect that excessive hollow in her waterlines aft slows her down, regardless of how powerful the crew is she tops out at 6.1 knots on gps with a fair old stern wave humped up behind her.
The Hanningfield Skiffs are 18ft long by 54" beam she is unashamedly a workboat with her centre of buoyancy well aft, paradoxically she is virtually as fast as the Gig.
The randan set up is great for short to medium races its main disadvantage being you have to be careful not to tangle up the oars on alternate sides.
Currently i am doin some sheer mods to the mould prior to laying up another one.

 

just curious about your opinion, about a similar idea to this being lengthened.
http://www.duckworksbbs.com/plans/gumprecht/cat12/index.htm

some catamaran stability, narrow beam pontoons maybe less water parting resistance, and the pontoons waterlines kinda "doubling" its length. theres the semi sitting up position, and the seat slides could be connected to help keep a cadence..

someplace else online, I'd seen a cat configuration where the pontoon-sponsons bottom faces were slightly deeper to the insides edges to minimize turbulence between them, and slightly asymetrical for less "funneling" type action.

I dont know if Mark Gumprecht is or isnt onto something really "fast+cool" with this concept, but kinda suspect it has some really good potential for it. thoughts?
just popping it out there, wish ya luck with some wins.

 

The catamaran concept for rowboats has been discussed on here before, do a search for Ro cat, there seems to be a fundamental increase in resistance over equivalent monohull, probably why they never caught on as rowing boats.

 

You have some misconceptions there.

The double hulls do not "kinda double its length". The wave drag will still be a function of the waterline length of each hull. The two narrower hulls will (barring interference effects) have a slightly lower wave drag than a single hull of of the same total displacement, but that wave drag will still be related to the actual waterline length.

The problem is that splitting the displacement between two hulls increases the wetted surface substantially, which means an equally substantial increase in drag from skin friction. For the types of hulls relevant to fast rowboats, this increase in skin friction tends to outweigh the reduction in wave drag.